The present invention relates mainly to a waterproof connector to be employed for connecting wire harnesses in an automobile.
FIGS. 3A-3C show a related waterproof connector as disclosed in Japanese Patent Publication No. 9-73947A. In FIG. 3C, reference numeral 1 represents a connector housing, 2 represents a rubber plug, and 3 represents a rubber plug holder.
As shown in FIGS. 3A and 3B, the rubber plug holder 3 and the rubber plug 2 are respectively provided with a plurality of through holes 5 and 7 in vertically arranged two rows which correspond to terminal receiving chambers formed in the housing 1 such that electric wires are passed through. At a rear face of the rubber plug 2, are provided three rectilinear slits 6 so as to interpose the two rows of the through holes 5 therebetween. At a front face of the rubber plug holder 3, are projectingly provided pressing plates 8 in a form of a flat plate which are adapted to be inserted into the slits 6 respectively.
In this waterproof connector, by inserting the pressing plates 8 into the slits 6 formed in the rubber plug 2 as shown in FIG. 3C, a compressive force is exerted on the rubber plug 2 increasing pressures around electric wires W so as to enhance a waterproofing property.
However, in the above described related waterproof connector having such a structure that the pressing plates 8 in a form of a flat plate are inserted into the rectilinear slits 6, a distribution of pressures around each of the electric wires W (a length of an arrow mark in the drawing represents,magnitude of the pressure) has not been uniform as shown in FIG. 3D. In other words, the pressures are larger at positions where the pressing plates 8 exist above and below, while the pressures are smaller at positions where the pressing plate 8 does not exist on the left and right hands, and a uniform distribution of the pressures has been unable to be obtained. For this reason, the related waterproof connector could not attain the waterproofing property of high performance.
Considering the above described circumstances, it is an object of the invention to provide a waterproof connector which can enhance the waterproofing property by equalizing the pressure distribution around an electric wire.
In order to achieve the above object, according to the present invention, there is provided a waterproof connector comprising:
a connector housing having a plurality of chambers for respectively receiving an electric wire;
a rubber mat plug having a plurality of bores respectively associated with the chambers, the rubber mat plug a front face of which is attached to a rear end portion of the connector housing;
a recess portion formed on a rear face of the rubber mat plug so as to surround the bores while remaining cylindrical wall portions surrounding the respective bores;
a plug holder for pressing the rear face of the rubber mat plug against the connector housing to hold the rubber mat plug thereon; and
a plurality of projections formed on a front portion of the plug holder and inserted into the recess portion to compress at least an outer peripheral face of the respective cylindrical wall portions so that a compressive force in a radial direction of the bores is generated to increase a sealing ability between the rubber mat plug and the electric wires passed through the bores.
Accordingly, the pressure distribution around the electric wire can be made uniform to the most, whereby the waterproofing function of high performance can be realized.
Preferably, the adjacent cylindrical wall portions are partly connected with each other.
Since the pitch between the bores can be minimized, although each of the cylindrical wall portions is not in a perfectly independent cylindrical form. Therefore, the compact waterproof connector can be realized.
Preferably, the respective cylindrical wall portions are formed so as to receive the compressive force from the projections at four portions situated on two orthogonal lines intersecting at the center of the respective bores.
Since each of the cylindrical wall portions receives the compressive forces in the four directions at the interval of 90 degree, the compressive forces can be exerted on the electric wire in a good balance.